information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Bladder wrack (Fucus vesiculosus)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.



The bladder wrack Fucus vesiculosus is a large brown algae, common on the middle shore. It can be found in high densities living for about 4-5 years (S. Kraan, pers. comm.). Under sheltered conditions, the fronds have been known to grow up to 2 m in Maine, America (Wippelhauser, 1996).

Recorded distribution in Britain and Ireland

All coasts of Britain and Ireland.

Global distribution

See additional information.


The species is found intertidally on rocky shores in a wide range of exposures. It is common on the mid shore often with Ascophyllum nodosum, below Fucus spiralis and in a zone further up the shore from Fucus serratus.

Depth range

Not relevant

Identifying features

  • Frond with prominent midrib and almost spherical air bladders.
  • Air bladders usually paired but may be absent in very small plants.
  • Margin of frond smooth.
  • Dichotomously branched.
  • The species may be confused with Fucus spiralis with which it hybridizes.
  • A bladderless form occurs on more wave exposed shores (S. Kraan, pers. comm.).

Additional information


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Biology review


AuthorityLinnaeus, 1753
Recent Synonyms


Typical abundanceHigh density
Male size rangeUp to 1.5m
Male size at maturity15-20cm
Female size range15-20cm
Female size at maturity
Growth formFoliose
Growth rate0.48cm/week
Body flexibility
Characteristic feeding methodAutotroph
Diet/food source
Typically feeds on
Environmental positionEpifloral
Is the species harmful?No

Biology information

Air bladders or vesicles are produced annually to make the frond float upwards when immersed, except at highly exposed coasts where no air bladders are produced (S. Kraan, pers. comm.). Fucus vesiculosus supports few colonial organisms, but provides substratum and shelter for the tube worm Spirorbis spirorbis, herbivorous isopods, such as Idotea, and surface grazing snails, such as Littorina obtusata.

Growth Rate
The growth rate of fucoids is known to vary both geographically and seasonally (Lehvo et al., 2001). Relative growth rate can vary from 0.05-0.14 cm/day depending on temperature and light conditions (S. Kraan, pers. comm.). The increase in growth rate for Fucus vesiculosus at 10, 12.5 and 15 °C was found to be, on average, 280% higher than it was at 7 °C (Strömgren, 1977). In the northern Baltic, the highest relative growth rate of vegetative branches for Fucus vesiculosus was observed in the summer (up to 0.7% / day ) compared to winter growth (less than 0.3% / day). In Sweden, growth rates of 0.7-0.8 cm / week were reported over the summer months of June and August (Carlson, 1991).

Growth rate can also vary with exposure. In Scotland, Fucus vesiculosus at Sgeir Bhuidhe, a very exposed site, grew about 0.31 cm / week whereas plants at Ascophyllum Rock grew an average of 0.68 cm / week (Knight & Parke, 1950). The proportion of energy allocated between vegetative and reproductive growth also varies throughout the year. In the northern Baltic, reproductive branches experienced a peak in growth rate in mid April where the relative growth rate was almost 0.1% / day (Lehvo et al., 2001).

Habitat preferences

Physiographic preferencesOpen coast, Strait / sound, Sea loch / Sea lough, Ria / Voe, Estuary, Enclosed coast / Embayment
Biological zone preferencesMid eulittoral, Upper eulittoral
Substratum / habitat preferencesArtificial (man-made), Bedrock, Cobbles, Gravel / shingle, Large to very large boulders, Pebbles, Small boulders
Tidal strength preferencesModerately Strong 1 to 3 knots (0.5-1.5 m/sec.), Strong 3 to 6 knots (1.5-3 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesModerately exposed, Sheltered, Very sheltered
Salinity preferencesFull (30-40 psu), Reduced (18-30 psu), Variable (18-40 psu)
Depth rangeNot relevant
Other preferencesNo text entered
Migration PatternNon-migratory / resident

Habitat Information

The morphology of the plant varies in response to the environmental conditions leading to distinct varieties. Also, the fact that it can hybridize freely with other fucoids leads to the formation of distinct varieties (S. Kraan, pers. comm.). This species can survive in exposed locations, even though it is not a preferred habitat, but survive as a dwarf form (S. Kraan, pers. comm.). Plants from exposed locations usually have no airbladders and are known as Fucus vesiculosus forma evesiculosus (formally Fucus vesiculosus forma linearis) which may be mistaken for Fucus ceranoides. The loss of airbladders is thought to be because they increase a plants drag, making them more vulnerable to being washed off by waves. Depth